Amyloid-β (Aβ) peptides can form protease-resistant aggregates within and outside of neurons. Accumulation of these aggregates is a hallmark of Alzheimer’s disease (AD) neuropathology and contributes to devastating cognitive deficits associated with this disorder. The primary etiological factor for Aβ aggregation is either an increase in Aβ production or a decrease in its clearance. Aβ is produced by the sequential activity of β- and γ-secretase on the amyloid precursor protein (APP) and the clearance is mediated by chaperone-mediated mechanisms. The Aβ aggregates vary from soluble monomers and oligomers to insoluble senile plaques. While excess intraneuronal oligomers can transduce neurotoxic signals into neurons causing cellular defects like oxidative stress and neuroepigenetic mediated transcriptional dysregulation, extracellular senile plaques cause neurodegeneration by impairing neural membrane permeabilization and cell signaling pathways. Paradoxically, senile plaque formation is hypothesized to be an adaptive mechanism to sequester excess toxic soluble oligomers while leaving native functional Aβ levels intact. This hypothesis is strengthened by the absence of positive outcomes and side effects from immunotherapy clinical trials aimed at complete Aβ clearance, and support beneficial physiological roles for native Aβ in cellular function. Aβ has been shown to modulate synaptic transmission, consolidate memory, and protect against excitotoxicity. We discuss the current understanding of beneficial and detrimental roles for Aβ in synaptic function and epigenetic gene control and the future promising prospects of early therapeutic interventions aimed at mediating Aβ induced neuroepigenetic and synaptic dysfunctions to delay AD onset.

Infection can result in substantial costs to animals, so they frequently respond by removing infectious agents with an immune response. However, immune responses entail their own costs, including upregulation of processes that destroy pathogens (e.g. the production of reactive oxygen species) and processes that limit the extent of self-damage during the immune response (e.g. production of anti-inflammatory proteins such as haptoglobin). Here, we simulated bacterial infection across a 1000-fold range using lipopolysaccharide (LPS) administered to northern bobwhite quail (Colinus virginianus), and quantified metrics related to pro-inflammatory conditions [i.e. generation of oxidative damage (d-ROMs), depletion of antioxidant capacity], anti-inflammatory mechanisms (i.e. production of haptoglobin, expression of the enzyme heme oxygenase, production of the organic molecule biliverdin) and nutritional physiology (e.g. circulating triglyceride levels, maintenance of body mass). We detected increases in levels of haptoglobin and d-ROMs even at LPS doses that are 1/1000th the concentration of doses frequently used in ecoimmunological studies, while loss of body mass and decreases in circulating triglycerides manifested only in individuals receiving the highest dose of LPS (1 mg LPS kg −1 body mass), highlighting variation among dosedependent responses. Additionally, individuals that lost body mass during the course of the experiment had lower levels of circulating triglycerides, and those with more oxidative damage had greater levels of heme oxygenase expression, which highlights the complex interplay between pro-and anti-inflammatory processes. Because low doses of LPS may simulate natural infection levels, variation in dose-dependent physiological responses may be particularly important in modeling how free-living animals navigate immune challenges.

The severity of Alzheimer’s Disease (AD) progression involves a complex interplay of genetics, age, and environmental factors orchestrated by histone acetyltransferase (HAT) mediated neuroepigenetic mechanisms. While disruption of Tip60 HAT action in neural gene control is implicated in AD, alternative mechanisms underlying Tip60 function remain unexplored. Here, we report a novel RNA binding function for Tip60 in addition to its HAT function. We show that Tip60 preferentially interacts with pre-mRNAs emanating from its chromatin neural gene targets in theDrosophilabrain and this RNA binding function is conserved in human hippocampus and disrupted inDrosophilabrains that model AD pathology and in AD patient hippocampus of either sex. Since RNA splicing occurs co-transcriptionally and alternative splicing (AS) defects are implicated in AD, we investigated whether Tip60-RNA targeting modulates splicing decisions and if this function is altered in AD. Replicate multivariate analysis of transcript splicing (rMATS) analysis of RNA-Seq data sets from wild-type and AD fly brains revealed a multitude of mammalian-like AS defects. Strikingly, over half of these altered RNAs identified as bona-fide Tip60-RNA targets that are enriched for in the AD-gene curated database, with some of these AS alterations prevented against by increasing Tip60 in the fly brain. Further, human orthologs of several Tip60-modulated splicing genes inDrosophilaare well characterized aberrantly spliced genes in human AD brains, implicating disruption of Tip60’s splicing function in AD pathogenesis. Our results support a novel RNA interaction and splicing regulatory function for Tip60 that may underly AS impairments that hallmark AD etiology.SIGNIFICANCE:Alzheimer’s Disease (AD) has recently emerged as a hotbed for RNA alternative splicing (AS) defects that alter protein function in the brain yet causes remain unclear. Although recent findings suggest convergence of epigenetics with co-transcriptional AS, whether epigenetic dysregulation in AD pathology underlies AS defects remains unknown. Here we identify a novel RNA interaction and splicing regulatory function for Tip60 histone acetyltransferase that is disrupted inDrosophilabrains modeling AD pathology and in human AD hippocampus. Importantly, mammalian orthologs of several Tip60-modulated splicing genes inDrosophilaare well characterized aberrantly spliced genes in human AD brain. We propose that Tip60 mediated AS modulation is a conserved critical post-transcriptional step that may underlie AS defects now characterized as hallmarks of AD.

Transfer of six thin-layer chromatography (TLC) Global Pharma Health Fund Minilab kit protocols for detecting fake or markedly substandard drugs in pharmaceutical products in the field to quantitative high-performance TLC (HPTLC)–densitometry methods was carried out using a model process published earlier. The developed and validated methods for tablets or capsules containing cefixime, cefuroxime axetil, cephalexin·H2O, ciprofloxacin HCl, levofloxacin, and metronidazole involved use of EMD Millipore Premium Purity silica gel 60 F254 plates, automated sample and standard solution application with a CAMAG Linomat 4, and automated densitometry with a CAMAG Scanner 3 for detection, identification, and quantification.

Alzheimer's disease (AD) is an age-related neurodegenerative disorder hallmarked by amyloid-β (Aβ) plaque accumulation, neuronal cell death, and cognitive deficits that worsen during disease progression. Histone acetylation dysregulation, caused by an imbalance between reduced histone acetyltransferases (HAT) Tip60 and increased histone deacetylase 2 (HDAC2) levels, can directly contribute to AD pathology. However, whether such AD-associated neuroepigenetic alterations occur in response to Aβ peptide production and can be protected against by increasing Tip60 levels over the course of neurodegenerative progression remains unknown. Here we profile Tip60 HAT/HDAC2 dynamics and transcriptome-wide changes across early and late stage AD pathology in the Drosophila brain produced solely by human amyloid-β 42 . We show that early Aβ 42 induction leads to disruption of Tip60 HAT/HDAC2 balance during early neurodegenerative stages preceding Aβ plaque accumulation that persists into late AD stages. Correlative transcriptome-wide studies reveal alterations in biological processes we classified as transient (early-stage only), late-onset (late-stage only), and constant (both). Increasing Tip60 HAT levels in the Aβ 42 fly brain protects against AD functional pathologies that include Aβ plaque accumulation, neural cell death, cognitive deficits, and shorter life-span. Strikingly, Tip60 protects against Aβ 42 -induced transcriptomic alterations via distinct mechanisms during early and late stages of neurodegeneration. Our findings reveal distinct modes of neuroepigenetic gene changes and Tip60 neuroprotection in early versus late stages in AD that can serve as early biomarkers for AD, and support the therapeutic potential of Tip60 over the course of AD progression.